This term is used specifically in the game Battlefield 2. It is the only full-proof method of teamkilling someone without being punished. Jet throwing is executed as follows:
1.) Obtain a jet.
2.) Find your target.
3.) Gain altitude.
4.) Fly directly at your target.
5.) Jump out of the jet at the last second.
6.) Laugh your ass off.
This method of teamkilling works even when teamdamage is disabled.